#include "erfa.h" #include int eraD2dtf(const char *scale, int ndp, double d1, double d2, int *iy, int *im, int *id, int ihmsf[4]) /* ** - - - - - - - - - ** e r a D 2 d t f ** - - - - - - - - - ** ** Format for output a 2-part Julian Date (or in the case of UTC a ** quasi-JD form that includes special provision for leap seconds). ** ** Given: ** scale char[] time scale ID (Note 1) ** ndp int resolution (Note 2) ** d1,d2 double time as a 2-part Julian Date (Notes 3,4) ** ** Returned: ** iy,im,id int year, month, day in Gregorian calendar (Note 5) ** ihmsf int[4] hours, minutes, seconds, fraction (Note 1) ** ** Returned (function value): ** int status: +1 = dubious year (Note 5) ** 0 = OK ** -1 = unacceptable date (Note 6) ** ** Notes: ** ** 1) scale identifies the time scale. Only the value "UTC" (in upper ** case) is significant, and enables handling of leap seconds (see ** Note 4). ** ** 2) ndp is the number of decimal places in the seconds field, and can ** have negative as well as positive values, such as: ** ** ndp resolution ** -4 1 00 00 ** -3 0 10 00 ** -2 0 01 00 ** -1 0 00 10 ** 0 0 00 01 ** 1 0 00 00.1 ** 2 0 00 00.01 ** 3 0 00 00.001 ** ** The limits are platform dependent, but a safe range is -5 to +9. ** ** 3) d1+d2 is Julian Date, apportioned in any convenient way between ** the two arguments, for example where d1 is the Julian Day Number ** and d2 is the fraction of a day. In the case of UTC, where the ** use of JD is problematical, special conventions apply: see the ** next note. ** ** 4) JD cannot unambiguously represent UTC during a leap second unless ** special measures are taken. The ERFA internal convention is that ** the quasi-JD day represents UTC days whether the length is 86399, ** 86400 or 86401 SI seconds. In the 1960-1972 era there were ** smaller jumps (in either direction) each time the linear UTC(TAI) ** expression was changed, and these "mini-leaps" are also included ** in the ERFA convention. ** ** 5) The warning status "dubious year" flags UTCs that predate the ** introduction of the time scale or that are too far in the future ** to be trusted. See eraDat for further details. ** ** 6) For calendar conventions and limitations, see eraCal2jd. ** ** Called: ** eraJd2cal JD to Gregorian calendar ** eraD2tf decompose days to hms ** eraDat delta(AT) = TAI-UTC ** ** Copyright (C) 2013-2015, NumFOCUS Foundation. ** Derived, with permission, from the SOFA library. See notes at end of file. */ { int leap; char s; int iy1, im1, id1, js, iy2, im2, id2, ihmsf1[4], i; double a1, b1, fd, dat0, dat12, w, dat24, dleap; /* The two-part JD. */ a1 = d1; b1 = d2; /* Provisional calendar date. */ js = eraJd2cal(a1, b1, &iy1, &im1, &id1, &fd); if ( js ) return -1; /* Is this a leap second day? */ leap = 0; if ( ! strcmp(scale,"UTC") ) { /* TAI-UTC at 0h today. */ js = eraDat(iy1, im1, id1, 0.0, &dat0); if ( js < 0 ) return -1; /* TAI-UTC at 12h today (to detect drift). */ js = eraDat(iy1, im1, id1, 0.5, &dat12); if ( js < 0 ) return -1; /* TAI-UTC at 0h tomorrow (to detect jumps). */ js = eraJd2cal(a1+1.5, b1-fd, &iy2, &im2, &id2, &w); if ( js ) return -1; js = eraDat(iy2, im2, id2, 0.0, &dat24); if ( js < 0 ) return -1; /* Any sudden change in TAI-UTC (seconds). */ dleap = dat24 - (2.0*dat12 - dat0); /* If leap second day, scale the fraction of a day into SI. */ leap = (dleap != 0.0); if (leap) fd += fd * dleap/ERFA_DAYSEC; } /* Provisional time of day. */ eraD2tf ( ndp, fd, &s, ihmsf1 ); /* Has the (rounded) time gone past 24h? */ if ( ihmsf1[0] > 23 ) { /* Yes. We probably need tomorrow's calendar date. */ js = eraJd2cal(a1+1.5, b1-fd, &iy2, &im2, &id2, &w); if ( js ) return -1; /* Is today a leap second day? */ if ( ! leap ) { /* No. Use 0h tomorrow. */ iy1 = iy2; im1 = im2; id1 = id2; ihmsf1[0] = 0; ihmsf1[1] = 0; ihmsf1[2] = 0; } else { /* Yes. Are we past the leap second itself? */ if ( ihmsf1[2] > 0 ) { /* Yes. Use tomorrow but allow for the leap second. */ iy1 = iy2; im1 = im2; id1 = id2; ihmsf1[0] = 0; ihmsf1[1] = 0; ihmsf1[2] = 0; } else { /* No. Use 23 59 60... today. */ ihmsf1[0] = 23; ihmsf1[1] = 59; ihmsf1[2] = 60; } /* If rounding to 10s or coarser always go up to new day. */ if ( ndp < 0 && ihmsf1[2] == 60 ) { iy1 = iy2; im1 = im2; id1 = id2; ihmsf1[0] = 0; ihmsf1[1] = 0; ihmsf1[2] = 0; } } } /* Results. */ *iy = iy1; *im = im1; *id = id1; for ( i = 0; i < 4; i++ ) { ihmsf[i] = ihmsf1[i]; } /* Status. */ return js; } /*---------------------------------------------------------------------- ** ** ** Copyright (C) 2013-2015, NumFOCUS Foundation. ** All rights reserved. ** ** This library is derived, with permission, from the International ** Astronomical Union's "Standards of Fundamental Astronomy" library, ** available from http://www.iausofa.org. ** ** The ERFA version is intended to retain identical functionality to ** the SOFA library, but made distinct through different function and ** file names, as set out in the SOFA license conditions. The SOFA ** original has a role as a reference standard for the IAU and IERS, ** and consequently redistribution is permitted only in its unaltered ** state. The ERFA version is not subject to this restriction and ** therefore can be included in distributions which do not support the ** concept of "read only" software. ** ** Although the intent is to replicate the SOFA API (other than ** replacement of prefix names) and results (with the exception of ** bugs; any that are discovered will be fixed), SOFA is not ** responsible for any errors found in this version of the library. ** ** If you wish to acknowledge the SOFA heritage, please acknowledge ** that you are using a library derived from SOFA, rather than SOFA ** itself. ** ** ** TERMS AND CONDITIONS ** ** Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions ** are met: ** ** 1 Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** ** 2 Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** ** 3 Neither the name of the Standards Of Fundamental Astronomy Board, ** the International Astronomical Union nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ** POSSIBILITY OF SUCH DAMAGE. ** */